Apparatus for cleaning gases



July 9, 19359 R. R. HARMON APPARATUS FOR CLEANING GASES Filed Jan. 16,1932 2 Sheets-Sheet l 7 30622 2)? Ear/Won July 9, 1935. R. R. HARMON 12,007,759

' APPARATUS FOR CLEANING GASES Filed Jan. 16, .1952 2 sheets-sheet 2 7 AI i 2: 'I

I i 52 i 11 5:: A T A A A M T f M f A: -22 i 43 4*45-5 I 19 :X, ll- 9 rt ted July 9, 1935 2,007,759

UNITED STATES PATENT: OFFICE APPARATUS FOR CLEANING, GASES Robert R.Harmon, Charlottesville, Va., assignor to Peabody EngineeringCorporation, New York, "N. Y a corporation of NewYorlr ApplicationJanuary 16, 1932, Serial No. 587,095

90mm. (01. zen-s9) This invention relates to. an improved appa liquidback to the spraying means from which it is ratus. for cleaning orpurifying industrial gases, discharged so as to again throw it out inthe form and is. particularly directed tomeans that will of spray, andthus Ifusea material portion of the first remove the coarser solidparticles, then the liquid over and over again in each spray zone andvery fine particles of dust and fume and also consequently eiiect'notonly a considerable savs tiny droplets of liquid from gases. ing in thequantity of liquid used but also reduce In the cleansing of gasescontaining large quanthe power required to create the spray. tities offinely dividedlparticles of-dust and fume, The accompanying drawingsillustrates one an intensive scrubbing of the gases by mechaniform ofapparatus for carrying out the invention,

cally created sprays of liquid is desirable as a first wherein I H 10step, because the greater portion of the larger Fig. 1 shows theimproved apparatus in vertisuspended particles of foreign matter may becal section. l I readily removed and carried. off from the gas and ig- 2illustrates p View Of the iq d p eadthe tendency toward deposition ofsuch matter er and its supply-pipe as viewed on the line 2-2 in theapparatus is accordinglyminimized, o g. l

After removing the bulk of the dust or fume Fig. Sshows across-sectional view through the by t sprays ofli'qujd, the-,efliciencyof the apshell, the section being taken on the line 3-3 paratus may'b ematerially increased by directing of Figthe gasagainst' suitableimpingement surfaces Fig. 4 illustrates another cross-sectional detail V2:) whereby "thelfiner particles of suspended subthrough the Shelltekenen the line O E- stance's still' in the gas are deposited, fromwhich Fi WS Still other c o -Sectiona detail they may be removed byscrubbing liquid. through the shell taken on the line" 5-5 of Fig. 1.

Unless the bulk of the dust or fume is first, i 6 u at s, n a a d avertiremovedin an unobstructedspray-zone however, cal sectional det ithrough e S ell a d t e an arrangement of bafiles or impingementsurstructures in the lowermost of the several confaces, suitable to trapthefiner particles, will be (l t a rapidly rendered useless by thedeposition of s ws a p a i Of a Portion of the Same heavy particles,with a, cons qiient stoppage of condensing-stage structures as viewed onthe line the apparatus. 'l--'| of Fig. 6.

I haveliherefore combined in my improved apsillustrates in p ve d tail aporso paratus an unobstructed sprayszone i hi h 1 tion of one of thebars of the grid which carremove the bulk of coarse dust or fume, thenparr es a se s of s ag e baffles, nd.v

tially' obstructed spray-zones in which smaller 9 ShOWS Vertical se e aldetail Of &

yparticles are removed from the gas and then I portion f o oftheperforated r ss-p ate mprovide a zone or zones in which I producehigh D y t condenser t s With the velocity jets of gas which impingeupon individual ba s an battles arranged above the Samebafiles whichremove the finest particles. The apparatus shownin the drawings and dis-I also provide means for. freeing the cleaned Closing the invention s Qw yp and gas of fairly coarse drops of water or mist, to dry includes a"vertical shell o easing having e 4;) the gas by imparting centrifugalmotion} to the gas- H at its tOm and a gas-outlet I! at 40 same. Q thetop theregf.

-In gas cleaning apparatus employing means'for A central shaft 13extends vertically in the centrifugally projecting spraysof liquidacross shell from the bottom tothe'top, being seated the path of the gasstream to beat out the heavier in a step-bearing 14 at the bottom, andconnected particles of dust therefrom, considerable expense at the .topthrough suitable gearing. with a mois incurred due to the complexityofthe centriftor l5 which imparts rotary motion thereto. ugal sprayeritself or the lack of means for eifect- The bottom l8 of the shell orcasing is deing recirculation of the liquid through the spraysigned soas to. retain a quantity of water into er. Recirculation is-quiteessential inorder to which the particles of dust and fume that areeconomize the total quantity of liquid which must removed from the gasmay be deposited, and a 50 come from an outside source. 1 draw-off pipel1 extends from the bottom of the By means ofmy present invention, Ieffect a shell to a ,clarifier structure l8 in which the considerablesaving in the quantity of liquid emremoved particles are separated fromthe water ployed by utilizing the force of the spray to imand the latterthen used again, as will presently mediately return material quantitiesof that same be more fully-explained.'

The interior of the shell or casing immediately above the gas-inlet I iis provided with what I term an unrestricted spray zone is in which thebulk of the dust or fume in the gas stream is removed.

While spray zones in the cleaning of gas have heretofore been employed,they have, in all instances within my knowledge been accompanied by theextravagant use of water, and as the water should be hot so as toprevent chilling the gas at that stage, any extravagance in the use ofwater means added expense of operation.

In mechanically creating a spray by means of a rotating elementcontaining a perforated wall through which water or other liquids arethrown by centrifugal action, it is apparent that the density of thespray will be proportional to the speed of the element, the number ofperforations the wall of that element contains and the volume of liquidpassing through the perforations; per unit of time, for any given speed.

For the removal of dust and fume from gases a very dense spray isdesirable, which means that a large volume of liquid must flowconstantly into the rotating element and unless the liquid is reused insome manner a great waste must result. I V

I have devised an apparatus for creating a very dense spray employing analtogether novel means of returning the sprayed liquid to the rotatingelement from which it was sprayed, thereby effecting a recirculation ofthe scrubbing liquid in each spray-zone and consequently materiallyreducing the volume of liquid which must be pumped from an outsidesource into the sprayer.

I therefore employ novel means in the spray zones of my apparatus bywhich I effect a con-' siderable saving in the quantity of water used ineach zone, in that I retard the downward flow of the sprayed liquid bycausing a considerable quantity of e same to be caught and immediatelyreturn to the spraying means, which latter again throws it out in theform of spray across the path of the gas, so that a material quantity ofthe same liquid will be used a plurality oftimes in each spray zonebefore it will pass down to the next zone beneath it.

To effect this novel operation, I mount on the central shaft l3 and inthe unrestricted spray zone IS, a receptacle having an annularperforated wall 2|, which receptacle will revolve at suflicient speed tocentrifugally throw liquid tangentially therefrom in the form. of spraywhich spray will travel across the path of the up-flowing gas stream tothe inner vertical wall of the shell l0.

This form of spraying is not in itself new, but I associate with thesprayer another and novel means whereby a material part of thetangentially projected spray will be caught around the internalcircumference of the shell and be directed back to the sprayer-fromwhich it was thrown.

The spray-return means, in thisinstance, consists of one or moreinclined troughs 22 sustained from the interior shell-wall and havinginwardlydirected upper ends 22, which curve inwardly away from theshell-wall toward the central shaft so as to overhang the upper rim-edge24 of the centrifugal sprayer-wall 2|.

It will be noted that the shaft and the sprayer 20 carried thereby, willrotate in the direction of projected spray will sweep up the inclinedtroughs thereby propelling the liquid up the troughs and over the toprim-edge of the centrifugal sprayer.

By means of this arrangement of troughs, a large proportion of thesprayed liquid will be returned to the sprayer 20 from which it wasprojected and again thrown out by the latter,

thus utilizing the same liquid a plurality of times, and effecting aconsiderable saving in the quantity of liquid-necessary to drive out thebulk of the dust or fume at this first or unrestricted spray-zone ll.

Above the unrestricted spray zone I8, I provide, in this instance, tworestricted spray zones 2! and 26 respectively.

The structures employed at each of these restricted spray-zones arealike and a description of one will as readily apply to the other.

In each of these zones, I employ a centrifugal sprayer 21 which issecured to the rotary central shaft and has an imperforate bottom, anannular perforated wall and which is open at the top, just as is thecase with the sprayer receptacle 2| beneath.

Each of these spray-zones 2i and 28 also has an annular trough 22 aroundthe interior of the shell and in a horizontal plane immediately beneaththe sprayer receptacle 21 and a branch trough 29, extends from theannular trough toward the central portion of the shell and terminatesover the open top of the sprayer receptacle beneath it, as and for apurpose that will presently be more fully explained.

Associated with each sprayer-receptacle 21 in the zones 2! and 26, arestationary screens 20 which encircle the receptacles and extendhorizontally across the shell but are spaced from the wall of the latteraround their outer circumferential edges. Each of these outercircumferential edges of the stationary screens has a depending annularflange ll whose lower edge extends into the annular troughs 22 and formsa liquid-seal joint with liquid in the latter to prevent gas frompassing under the annular flanges and upwardly through the annularspaces 32 between the flanges 2i and the shell wall.

In these restricted spray-zones and 26, I also make use of inclinedtroughs I! about the shell-wall whose upper ends 24 turn toward thecenter of the shell and overhang the sprayer-receptacles 21 whereby todirect the sprayed water upwardly and back into the receptacles fromwhich it was thrown in the form of spray, and a saving in waterconsumption is here effected by reason of the fact that the same wateris utilized a plurality of times.

Also in these zones 25 and 28, water is sprayed horizontally from thereceptacles 21 across the stationary screens ll, up through which thegas stream is flowing and the upward flow and the pressure of the gasprevents the water from passing down through the screens themselves.

In the upper portion of the spraying zone 26 and over thespraying-receptacle 21 I provide a hollow cone-shaped water-spreader 25which iscarried at the inner end of a water-supply pipe 26 so that waterentering the hollow spreader from pipe 30 will be given a whirlingmotion as it is delivered into the centrifugal sprayer-receptacle 21beneath it.

Pipe 26 extends to a pump 21 which latter draws clarified hot water fromtank I! and forces it back to the spreader I! where it again graduallymoves downwardly through the zones 28, 25 and the. bulk oi the coarse-dust, followed by partially l are removed a r s, r :,-1

A I the operation, I ilndthatthe.

gas may still contain very fine suspended particles of dustoriume, whichsprayszcannot remove, and

i. so.

increased by means or steam or hot water sprayed into. thegasfrom pipe38; and preferably controlled hya thermostatically actuated valve 39.

It will thusbehotedthatl use improved apparatusan unobstructed sprayzone to remove obstructed spray zones inwhichsmaller particles At thisstage of ,I have found that by translating gas-pressure intogas-yelocity by providing a perforated grid 1 and numerous impingementsurfaces against 20 which the gas must strike, without obstructing thegas-flow-aiterit strikes. such'suriaces, that these ilne dust particleswillbe removed from the .gas by, impact with suchsurfaces from which ofthe' gassstrearn, as. will presently be more fully reference being madethey may be washed and carried oft from the path explained.

most spraying zone 26, aswill now beexplained, to Figs. 1,.6,-- 7', 8and 9 of the drawings. 2

of the-shell and, opens into the said troughior conveying off water orliquidjwhich flows .downwardiy in the shell fromabove; i

' condensation of the vapor. in the gas and impingemerit, and ,preventsthe bulk of cooling. water from vdescending into .the spray .zones where,humidificationof the gas is taking place.

The condensed vapor builds upon the dust, and fume particlesandincreases their mass, and size, forming :droplets which serve asvehiclesfor carrying off the dust or fume particles upon impingement ofthe former against the bailles hereafter described, and the subsequentwashing of thebailles by the cooling water flowing into'troughfl, andthence into pipe 4i. The dust-centered droplets are therefore*removedirom the gas stream and carried off in suspension in thecoolingwater "instead of y'p pitation down throughthat "stream. q

Directly above the trough 40,1 provide the-interior of the shell illwith a plate or plates 42having Venturi-like orifices 4l-and withanannular 5 depending rimfiange 44,. which is imperforate I andwhich-depends inthe trough-40.

The diameter or .the assembled plate or plates 42 is. or are suchthatits rim-flange. 44 isspaced from the-wall of -:the ,shell in order thatwater from above may flow down between said flange and shell-wall asclearly shown in Fig. .6, for it must be understood that the pressure ofthe upfiowing gas throughthe orifices 48 of the plate will prevent wateron; top of, the latter from passing down through those orifices. I

Aswater thereforefiows downintothe trough 40, it williorm aseal aboutthe flange and prevent the gas from. passing upwardly around saidflange. v

,theplate beneath. 7

. By this arrangement otbars and bailies a comparatively cheap grid isvformed and each bar thezoneio.

. sideslot thebars. :37 reference to Figs, .1 and -it.will be seen thatalternate bailles 4' project from the same side with spaces therebetweenthereby producing-alternate bellies and spaces at the same side 01 thebar.

The perforations or oriflces4lin plate are so positioned that when aballle-baris placed thereover the bailles will overlie the orifices inwhen positioned will provide bailies over a considerable number oforiilces.

, As thegas passes throughtheoriflces, the pressure is translatedpartlyinto velocity and a pluralityv of jets are formed which pass upthrough the water overlying the plate or plates where cooling occurs andadditional vapor iscondensed,

".andthisvapor condenses on the line particles or t One form orstructure torcarrying this idea intopractical eifecttis disclosed inthedrawings f andis located in the shell" above .the upper-.

dust and'iume present in the gas, causing the as centers. As the-gasthenimpinges against the;

ba'illes ,the particle-centered dropletsladhere' thereto and are therebyheld from on with I the up-flowing gasestream but areimmediatelyImmediately above;the sprayingrzone'26, 1 provide the interior of theshell wall with anannular trough 40 anda pipe 4i extends throughthe wallwashed away laterally by the how of water around the baiiies andoverthetop of the plate or plates..-

lust beneath one or more overflow troughs 4 l.

These overflow troughs extend-down Irom another annular trough 49 of asecond condensing zone 50. a t

This latter condensing; zone has an arrangement substantially like thecondensing zonebeheath it, inthat it has another plate or plates I withorifices, 52 and anannuiardepending flange f I 53 which depends into theannular trough n In this secondcondensing zone 80, I also provide a grid54 with baflles 55 overthe orifices]! 'so'that a secondcondensation ofvapor may take place on remaining fine dust particles still in the gas,

. tobe removed by impingement. against the bailles i5 and also washedaway by waterflowing across the baflles and plates and emptying intotrough 49. In this second condensing zone SI, the annular ,trough 49 isconnectedwitha pipe 50 in which there is a valve 51 whichis actuated bya thermostat 58 which is controlled by temperature in Also in condensingzone 50, I provide a spreader N that is supported from the plates 50beneath which spreader receives ,water. from overflow troughs 60 thatextend down from another annu- The annular trough 4| lnthe uppermostcondensing stage 82, isalso connected with a pipe I! Ill) lar trough iiin an uppermost condensing stage v in which there is a valve 64 which isactuated by s a theromstat 16 in the zone or, stage 42.,

This uppermost condensing zone or stage 62 grids with bai'lles"projectingtherefrom tooverlie the'orince Ii.

. A spreader .plate I is also over the aisoha Plates "with orifices I!and an annular baiiies in this latter condensing stage or zone 62 sothat liquid iroman annular spreader ll may be"'directedlaterally'overthe bailles and plates beneath.

A pipe II supplies liquid continuously to the spreader ll.

In this uppermost condensing zone or stage I,

the remaining fine particles in the gas-stream are removed and washedoff laterally from the gas-stream in the form 'of particle-centereddroplets." I

. .When the gas-stream passes through the uppermost condensing stage orzone '2 due to the violent impact of the gas against the baiiies in thezones or stages beneath, relatively large drops of water may remainin-the' gas stream and be carried along with the latter. To remove thesewater-drops, I provide a series of curve vanes I! through which thegas-stream must pass and during this passage of the stream of gas,centrii'ugal movement is imparted to it and the water drops are thrownand beaten out and trickle downwardly on the shell.

It will thus be seen that inmy invention, I first pass the gas throughunrestricted and then restricted spraying zones where the largerparticles of dust and fume are removed and humidiilcation takm place,then I pass the gas stream through a' series of condensing stages wherethe finer particles areremofved by condensing the vapor on the particlesand forming droplets which serve as and conserved.

. I have found in actual practice that an apparatus embodying thefeatures above set forth will produce a cleanliness in the gas notheretofore achieved by any processor apparatus within my v knowledge.

Having-described my invention, I claim,-

l. In an apparatus for cleaning gases the combination of an uprightcasing having a-gas-inlet near its bottom and a gas-outlet near its top,of a'plura'lity'of spraying zones in the casing and eachzone having arotary centrifugal sprayer','and spirally-inclined troughs around thewall of the casing which lead upwardly and over the sprayers whereby thespray from the sprayer will be driven into the inclined troughs anddirected up and over the tops of and back into the spray- 2. In anapparatus for cleaning gases the combination of'a casing having agas-inlet and a gas-outlet, of means in the casing for iirst removingthe coarser particles of matter from the gas-stream, a plate extendingacross the path of the gas-strea'm-in said casing said plate having adown-turned rim flange that is spaced from the interior of thecasing-wall, an annular liquid trough on the casing into which therimflange' depends so that the rim is liquid-sealed, and said platealao'having a series of perforations to translate thepressure of thegas-stream into gas-velocity and form gas-jets, a stationary grid aboveand slightly spaced from the'plate said grid having a series of barswith bailles projecting from opposite sides thereof and overlying theperforations to intercept the Jets of gas and separate the fineparticles from the gas, and means for washing the bailiea of the grid tocarry on the intercepted particles. 3. In'an apparatus for cleaninggases the combination of a casing having a gas inlet and a gas outlet,rotary spraying 'means in the casing, means for feeding liquid to therotary means to be thrown centrifugally across the path of the gasstream and stationary liquid-elevating means in the casing for catchingand elevating the centrifugally-thrown liquid to the top of the rotarymeans from which it was thrown, said liquid-elevating means beingindependent of all rotary means.

4. In an apparatus for cleaning gases the combination' of a casinghaving a gas inlet and a gas outlet, rotary spraying means in'thecasing, means for feeding liquid to the rotary means to be throwncentrifugally across the path of the gas stream-and stationaryliquid-elevating trough means carried by the casing-wall and from thewall and terminate over the rotary sprayer for catching the thrownliquid and conveying it upwardly and back into the top of the rotarysprayer from which it was thrown.

6. In an apparatus for cleaning gases the combination with a casinghaving cleaning zones each of which is provided with a cross-platehaving rows of perforations, the perforations in onerow being arrangedin staggered relation with respect to those in the next row, a series ofedgewise bars extending over each of said plates between adjacent rowsof said perforations and each bar having a series of bailles extendinglaterally therefrom and at opposite sides thereof, the bailies at oneside of each bar being in staggered relation with respect to the bafflesthat extend from the-other side of each bar whereby the bailles willoverlie the staggered perforatio in the plate immediately below.

7. In an apparatus for cleaning gases the combination withaa'casinghaving cleaning zones each with a plate having perforations which thegas is made to pass inlets, bars extending edgewise across the casingabove each of the said plates but spaced'above the latter and each barhaving at its opposite sideaa series of bafiies which'proiecthorizontally therefrom, the successive baffles at each side of -a barbeing spaced from each other so as to form alternate bailes and spaces,the baiiles at one side of each bar being disposed opposite the spacesat the other side of each bar and all of the bailles being formedintegrally with its bar and the horilontal bailies of said barsoverlying the perforations in the platebeneath.

8. In an apparatus for cleaning gases the combinatlon with a casinghaving-a gas inlet near its bottom and a gas outletnear its top, of aplurality of cleaning some in thefcasingbetweenthegasinlstandtheg'aso'atfiteachaonehavbars eachhaving laterallyextending baili'es sepmg a perforated plate with bmi eixtenamg' ever butspacedirom the upper side zthereot and said arated by spaces along itslower opposite sides 6 which bailles are formed integrally withsaid barsnd overlie theperforationsin the plate beneath,

,imeansior supplying a body ot wateracross each perforated plate and itsassociated baillesand' ma series of curved blades in the casing between0 the uppermost submerged plate and its bames vand'the gas outlet fromthe casing for eliminating moisture carried torward'by the sasas itleavesthe uppermost or water. 9.-In an apparatus-for cleaning ga'sesthecombmation' oi sinah l, 1111 receptacles carriedon said shalt betweenthe inletiand outlet; saidreceptacles having a pertorated annular walland an imperforate bottorn for spraying liquid across the path of thegas streamhians torteeding liquid into said 791 7 receptacles andliquid-elevating menu in the casing about each. rotary zreceptacletorcatching anddirecting the sprayed iiqnid'upward- 1y outside or and backover the top of the receptacle from which it was thrown, saidliquidelevating means beins independent of said rotary receptacles.

ROBERT R. EAR-HON.

